Dry-pipe sprinkler system



1,608,105 g. w. KNIGHT DRY PIPE SPRINKLER SYSTEM Filed Dec. 9, 1924INVENTOR. IRA W. KN IGHT A TTORNEYS Patented Nov. 23, 1926.

UNITED. srArl-zs PATENT OFFICE.

IRA wQimre'nr, OF CRANSTON; RHODE ISLAND, ASSIGNOR TO GENERAL FIRE EX-TING-UISHEB COMPANY, OF PROVIDENCE, RHODE ISLAND, A CORPORATION OFDELAWARE.

nnr-rrrn srnmxmn sYsm-p Application filed December 9, 1924. Serial No.754,848.

This invention relates to improvements in dry pipe sprinkler systemshaving a booster pump for providing a suflicient 0 rating head to insureadequate sprinkler discharge.

More especially it relates to apparatus or effecting the operation ofsaid pump before dry pipe valve opens, whereby its tripping may behastened and the discharge v accelerated.

In my pending. application Serial No. 7 54,847 there is dlsclosed asystem in which the actuation of the booster pum is dependent upon thetripping of the ry pipe valve, there being a pressure responsive devicewhich efiects starting of the pump motor upon rise of pressure in theintermediate chamber of that valve. where the water pressure supply isextremely low, or when it is greatly reduced by adjacent fire engineor.other pumps; a suflicient rise of pressure to effect pump actuationma not occur in the intermediate chamber; or 1t may be much delayed, dueto the necessity of bleeding the air pressure to practically zero,before the pressure is low enou'gh to let the valve trip.

The presentinvention is to cause earlier starting of the pump, thus tobring about the positive opening of the dry pipe valve irrespective ofthe supply pressure. A feature is the arrangement and combination ofcircuits through an accelerator which responds to a drop in pressureinthe distributin g line,. and through a circuit closer which. respondsto a rise of pressure, to the end that each device may perform its indi-'vidual function without interfering with the other, and yet theseparate actions of both shall combine to produce early and continuousoperation of the pump.

' Apparatus by which the invention may be practiced comprises the usualsupply and distributing piping with a dry pipe valve and abooster pumpinterposed between the supply". main and the valve. The pump is drivenby an electric motor whose current passes through a starting andcontrolling rheostat the actuation of which rheostat is -in turn subjectto a shunt circuit from the main power wires. This shunt circuit may beset open or closed by the armature of-a.

solenoid the energization of which may be efiected by either a'pressurefall device attached to the distributing pipes, or by a ressure risedevice whic may for examp e be In places connected with the intermediatechamber of the dry pipe valve and normally 0 en to atmos here asdisclosed in my sai pending app ication. This double control is accomplished by arranging the energizing circuit in parallel thro'u hthesetwo devices so that the closure of eit er establishes current flow.

The accelerator of the present invention is connected with the system onthe air side of the dry pipe valve and may be set to respond when theair pressure has fallen to a predetermined degree which may either bethat at which the dry pipe valve would open if there were present anormally suflicient 'anddesirable water pressure, of if desired may besomewhat in excess of that, in which case the same effect is gained asif there were a high water pressure. The bleeding-of the air systemthrough'an open sprinkler head down to this pressure operates to closethe ener 'zing circuit, and so to effect operation of t e pump. Thisproperly builds up water pressure against the still closed dry pipevalve, and causes it to open which thus occurs long before the airpressure has gotten. down to the level corresponding to the actually lowWater pressure. The flow of water into thevalve chamber also fills thebranch pipe leading to the circuit closer which responds to rise inpressure, and operates it in throw its switch. Thus, the ener gizingcircuit is doubly closed, as it were,

cause the pressure rise device,'having. already operated, keeps theenergizing circuit closed. Thus the pump action, initiated by pressurefall, is maintained notwithstanding the ensuing pressure rise, giving acontinuous water pressure supply to the sprinkler.

It is intended that the suitable expression in the appended b patentshall cover, cbaims, whatever features ofpatentable novelty exists inthe invention disclosed.

In the accompaning drawings the single figure is an elevation showing abooster sprinkler system embodying the invention,

parts being shown somewhat diagrammatically.

Referring to the drawings, the supply main 10 leads to a booster pump 12which discharges into the riser 14 leading to the dry pipe valve 18. Asillustrated this valve is of the differential type, although theapplication of the invention is not limited to' that, in which a waterclapper 16 holds bacls the water in riser 14 so long as the pressureupon the clapper 20 of air in the distributing pipes 22, is greatenough, and until said pressure is reduced by escape of air through thesprinkler heads 24, when one or'more is opened.

The opening of the dry pipe valve permits the water to flow into itsintermediate chamber, thereby closing its vent 26 which is normally opento atmosphere, and thence through a small pipe 28 to a device 30 1nwhich a switch 32 is operated by rise of pressure to close a circuitfrom the source of energy 34 through solenoid 86. The armature of thelatter when drawn upward upon energization of the solenoid rests acrossterminals 38 of a shunt'circuit S whose current controls the operationof: rheostat 40. This in turn governs the operation of the motor 42which drives the booster pump 12.

If the supply pressure in main 10 and and riser 14 Were very low, dueperhaps to other demands being made upon the supply, the bleedingreduction of the air pressure might not effect a tripping of the drypipe valve or might be very long in doing so, and consequently thebooster pump would not be started bythe pressure rise device. To preventthis, the present invention pro vides another circuit closer 44, hereincalled an accelerator, connected to the distributing line 22 beyond thedry pipe valve on the air side. This operates upon fall of pressure toclose a switch 46 which forms part of the energizing circuit through-thesolenoid 36. This part of the circuit is arranged in parallel with thatpart which passes through the other circuit closer 30, so that if eitherswitch is closed, the circuit from the battery through the solenoid willbe made. Since the accelerating device operates upon fall of pressure inthe distributing pipe to close its switch and thus to effect pumpoperation, it acts oppositely upon rise of pressure and opens theswitch. But before its opening can thus occur, the pressure generated bythe booster pump will have opened the dr pipevalve and caused thepressure rise evice 30 to close its switch, Thereafter it will notmatter that the switch of the pressure fall device is opened by theelimination of the low pressure condition, for the circuit through thesolenoid will still be closed and the pump thus be continued in motion.

The startin of the pump is efiected by the pressure "all device ahead ofthe opening of the dry pipe valve, whenever the air pressure has beenreduced following the opening of a sprinkler head to a degree which maybe predetermined to give as early orlate response as desired. By thismeans, in a locality where the city water pressure is low or is liableto fail, but where the pump 12 is capable of boosting the pressure to acertain known standard at the dry pipe valve, the accelerator 44 can besctso that the valve will open when the air has. fallen to one-sixth ofthat pressure (assuming the valve to operate on a 6 to 1 ratio of waterpressure to air pressure)- without waiting for the air pressure to dropto one-sixth of the actual city Water supply pressure. This makes theaction of the system analogous to that of a system having the saidstandard of pressure actual- ,ly available in the city supply. Oncestarted, the pump is maintained running by vthe pressure rise device, sothat an effective discharge will be continuous until the system isreset.

I claim:

1. A sprinkler system having the combination, with a dry pipe valve anda booster pump, of pump control means havlng a connection with thesystem on the air side of said valve and another connection with thesystem on the delivery side of the pump, and comprising devicesresponsive to pressure changes in the system adapted upon the fallofpressure on the air side of said valve to initiate actuation of the pumpand upon rise of pressure on the delivery side of said pump to maintainthe pump actuation.

2. A sprinkler system having the combination, with a dry pipe valve anda booster pump, of pump control means including an electromagneticdevice having two circuit closers; a pressure responsive deviceconnected to the system on the air side of said dry pipe valve andadapted upon fall of pressure in said pipes to set one of said circuitclosers whereby the pump is put in operation, and another pressureresponsive device connected to the system and adapted upon rise ofpressure therein to set the other of said circuit closers so as tocontinue the position of the electromagnetic device and maintainpumpoperation after the first said pressure responsive device has beenmade inefiective therefor by rise of the system-pressure.

3. A sprinkler system having the combination, with a dry pipe valve anda booster pump, of pump controlrmeans including an electromagneticdevice having two circuit closers; a pressure responsive deviceconnected to the system on the supply side of the air clapper of saidvalve normally open to atmosphere and adapted upon rise of pressure inthe system to set one of said circuit closers to effect operation ofsaid pump; and another pressure responsive device connectedto the systemon the air side of said clapper and adapted upon fall of system pressureto a predetermined degree above the atmosphere to set the other circuitcloser for effecting pump operation, thereby causing a rise of pressurein the system to which the first mentioned device responds to efiectcontinuation of said pump operation.

Signed at Providence, Rhode Island, this 17th day of October, 1924- 'IRAW. KNIGHT.

